Electronic switches and circuits



5,' 1961 R. R. NEWSOM ELECTRONIC SWITCHES AND CIRCUITS Original Filed mazo, 1949 3 Sheets-Sheet 2 N H H 25 EES Su 3; Q-

-l L. E E NN ll INVENTOR.

Roy R. Ne wsom ATTORNEY Dec. 5, 1961 R. R. NEWSOM 3,012,101

ELECTRONIC SWITCHES AND CIRCUITS Original Filed May 20, 1949 5Sheets-Sheet 3 Line Am lifiers Ti g.3

INVENTOR. Lu] Roy R. Newsom BY m 1 w ATTORNEY United States Patent 3Claims. (Cl. 17915) The present invention relates to electronic switchesand circuits associated therewith, and more particularly to electronicswitches of a novel type and various circuits and instruments usabletherewith.

This application is a continuation of my copending application SerialNo. 94,432., filed May 20, 1949, now abandoned.

An object of this invention is to provide a new electronic instrumentwhich performs a switching action without impulse distortion of any kindand specifically Without the electrical disturbances usually associatedwith mechanical relay or revolving switch actions.

Another object of this invention is to provide a new electronicswitching device useful in various types of circuits for inducingseparate signals derived from separate sources onto a single carriersystem.

A further object of this invention is to provide an elec tronicswitching device which permits the simultaneous observation on thescreen of a cathode ray tube of a number of electrical signals derivedfrom separate sources.

A further object of this invention is to provide an electronic switchingdevice which permits the simultaneous or separate observation on thescreen of a cathode ray tube of selected separate electrical signalsderived from separate sources.

Another object of the present invention is to provide an electronicswitching device in which the impulses imposed on the separate carriersystems are time-spaced in accordance with the requirements of theinstallation by means of controls for independently changing thefrequency and duration of the separate impulses.

Another object of this invention is to provide an electronic switchingdevice which provides separate carrier impulses in separate circuitsthereof, said carrier impulses being time-spaced with relation to eachother.

A still further object of this invention is to provide an electronicswitching device of the foregoing character in which provision is madefor the imposition of separate signals on said carrier impulses.

Another object of this invention is to provide an electronic circuit inwhich the amplitude of the signals imposed on the carrier impulses maybe varied independently of the amplitude of any other signals by meansof controls on the signal input circuit of this device.

A further object of this invention is to provide an electronic switchingdevice in which all of the carrier impulses are amplified by the sameamplifier channel.

Other and important objects and advantages of the present invention willbe apparent from the following description and drawings in which:

FIG. 1 is a block diagram of the circuits of this invention in which theinput and output electrical wave shapes of each stage in the circuit areshown;

FIG. 2 represents a wiring diagram showing the component elements ofthis invention as used in conjunction with a cathode ray oscilloscope;and

FIG. 3 represents a wiring diagram showing the component elements ofthis invention as connected in a conventional type circuit for thisinvention.

This invention provides a crystal oscillator having frequency driftcontrol in the grid circuit adapted to pro-- vide an oscillating currentof desired frequency. The

output of the crystal oscillator is fed into the primary of atransformer having a center tapped secondary and the opposite ends ofthe secondary lead to the grids of two separate voltage amplifier tubes.By reason of this transformer connection the. voltage derived from theseparate amplifiers will be time-spaced the equivalent of electricaldegrees. The output of the separate amplifiers is passed throughparallel phase shifting circuits to divide the output and speed or delaythe wave impulses thus providing further time separation of the voltageimpulses passed into the next stage of the circuit.

The next stage comprises a series of vacuum tube limiter circuitsadapted to square the wave form introduced. From these tubes the outputis delivered across a short timing constant to peak the square wave formand then into a second limiter circuit adapted to clip the wave form toa positive or negative impulse as desired. As a result of theaforementioned circuits a plurality of carrier impulses are derivedwhich are so timed and spaced that there will be no interference betweenthe separate carrier impulses when the system is properly tuned. Thesecarrier impulses may be all fed to the same carrier line and theseparate divided impulses will not interfere with each other because ofthe time spacing.

As a further development of this invention a circuit is provided bymeans of which separate signals may be imposed on the carrier impulsespreviously mentioned. Preferably the input signals are passed through acompensated voltage divider to the grid of a cathode follower circuit.By means of this arrangement the separate input signals will be imposedon the carrier impulses only when the cathode follower tubes areconducting. Because of this arrangement it will be seen that it ispossible to impose a considerable number of input signals on a singleoutput carrier line without distortion or interference. This advantageof this invention may be used in various situations to increase thecapacity of carrier circuits and lines. Its application to telephonecircuits and the like can be readily seen inasmuch as it would make itpossible to increase the capacity of the telephone carrier circuits indirect proportion to the number of time separated carrier impulsesgenerated by this electronic switching device. Application of thisinvention to a special circuit analyzing device is shown in FIGS. 1 and2 in which the output carrier impulses are fed to the verticalamplifiers of a conventional type oscilloscope. When so used thisinvention provides a means for observing the wave forms of a pluralityof separate circuits simultaneously or separately as desired.

Referring now to the drawings the details and operation of thisinvention will be more clearly set forth.

The basic circuit of this invention is shown in schematic form in FIG.3. In this figure an oscillator tube T-1 is provided having frequencydrift control including a crystal 10 in the grid circuit. Through use ofthis crystal oscillator circuit a sine wave alternating current ofregulated frequency is induced on the primary of a transformer 11 havinga center tapped secondary. The op posite terminal ends of thetransformer secondary lead respectively to the grids of amplifier tubesT-2 and T-3. Since the potential thus imposed on the grids of theamplifier tubes T-Z and T-3 is derived from opposite ends of thetransformer secondary, it is apparent that the grid potential of tubesT4. and T-3 will be 180 out of phase. Accordingly the outputs of theamplifiers T-Z and T-3 are 180 out of phase though of increasedamplitude.

The plate outputs of the amplifiers T-Z and T-3 are next connected tosimilar parallel circuits in each of which the voltage is divided topass respectively across a resistor circuit, a resistor inductance or L/R circuit and a resistance capacitance or R-C circuit. The resistorcircuits for the tubes T-Z and T-3 comprise adjustable resistances 12and 12a, respectively, connected in series with fixed resistors 13 and13a, respectively. The L-R circuits for the tubes T-Z and T3 compriseadjustable resistances 14 and 14a, respectively, and inductances 15 and15a, respectively. Similarly the R-C circuits comprise adjustableresistances 16 and 16a, respectively, and capacitors 17 and 1711,respectively. The time constants of these respective circuits are suchthat while the voltage across the pure resistance is practically inphase with the amplifier plate voltage, the voltage across thecapacitance lags the amplifier output by 60 and the voltage across theinductance leads the amplifier output by 60. Considering the circuitsconnected to the amplifiers T-2 and T-3, this arrangement provides anoutput of six sine wave voltages at oscillator frequency spaced at 60and of approximately 73 the amplitude of the amplifier output. In otherwords the voltage of each separate circuit is time spaced apart /6 ofthe oscillator frequency. The even spacing of these voltages isimportant in this invention and it will be noted that means are providedfor tuning the separate circuits to obtain the correct interval betweenthe separate circuits.

The time-spaced sine wave voltages in the six separate circuits are nextpassed to six square wave limiting circuits as represented by the triodelimiters T-4 to T-9. These triode limiters use grid limiting and cutoffaction to square the sine waves. If desired diode or duo-diode limitersmay be used by readapting the circuit. The evenly time spaced squarewave outputs from the separate limiter circuits are next taken acrossshort R-C time constant circuits to produce a peaked pulse output. Thesecircuits comprise capacitors C4 to C-9 connected respectively in serieswith resistors R-4 to R9. If desirable a coil or vacuum tube could beused in place of the R-C time constant. These peaked pulses are then fedto duo-diode clipper tubes indicated at T- to T- inclusive which clipthe positive going peaks to a positive reference potential. Likewise thenegative pulses are limited by the diode limiting action.

By reason of the foregoing the outputs from the duodiode tubes T-il) toT15 are six evenly spaced positive pulses of short time duration andlimited to a predeterined positive reference potential. It should benoted that by reason of the peaking circuit and the subsequent pulseclipping, the time duration of the six separate pulses is so limitedthat there will be time separation between each of the separate pulses.Since the pulses are time separated, the six circuits from the duo-diodeclipper tubes could all be connected to a single line withoutinterference between the separate pulses even though the pulse rate issix times the rate of the original oscillator frequency.

This time spacing of the separate pulses can be used in many ways inconventional electronic circuits. Generally it will be desirable toinduce separate signals on these separate pulses before they are fed toa single carrier line. A means for inducing such separate signals on thesix time spaced pulses is likewise shown in the FIGS. 1, 2 and 3. Inthese figures it will be seen that six separate lines L-l to L-6 areprovided upon which separate input signals may be imposed. These signalsare fed across compensated voltage dividers D-l to D-6 to the grid ofcathode follower tubes T-ld to T-Zl which are biased below cutofi andnormally not conducting. The time spaced pulses from the duo-diodeclipper tubes T-lil to T-IS are likewise fed to the grid of the cathodefollower tubes T-16 to T-Zl. The positive pulse will in eifect raise thebias of the cathode followers Tl6 to T21 so that the tubes will conductwhen and only when the positive pulses are imposed on the grids.

By means of this arrangement the input signal impulses upon each cathodefollower grid will be passed to the output cathode resistor only whenthe time spaced positive pulses arrive at each tube. The output from thecathode resistors indicated as six adjustable resistors R-16 to R-Zl,inclusive, is then fed to a single carrier line which by reason of thiscircuit will carry without distortion six times spaced pulses havingseparate signals imposed on each pulse. As shown in FIG. 3 this separatecarrier line can then be led to line amplifiers or other conventionalcircuits for any use desired. Application of this circuit to thecommunication industries will be readily apparent. For instance, thecapacity of conventional telephone lines could be increased considerablyby use of the circuits of this invention. Since the carrier pulses aretime spaced sufficiently to obviate any interference, the number ofmessages or signals carried by each separate pulse could be increased tothe same extent now possible through the use of multiple frequencies.

Application of the basic circuits shown in FIG. 3 to the special purposeof providing a cathode ray oscilloscope capable of presenting aplurality of wave forms on a single screen is shown in FIGS. 1 and 2.The actual circuit employed is shown in FIG. 2. Here it will be notedthat the output from the cathode follower is connected to the verticalamplifiers while the output fromv the duodiode clipper tubes T-li), T-lland T-il2 is fed to the upper vertical plate and the output from theduo-diode clipper tubes T13, T-iand T-lS is fed to the lower verticalplate of the oscilloscope. The square wave output from the tube T-4 isapplied to the paraphase amplifier grids of one sweep generator, therebyproviding a single time base circuit for the signals from tubes T-16,T-17 and T-18. Also the square wave from the tube T-i may be applied tothe paraphase amplifier grids of the second sweep circuit to provide aseparate time base for the signals from tubes T-19, T-Ztl and T21. Sincethe two square waves from T-4 and T-7 are out of phase they will providealternate synchronized operation of the two sweep circuits. If desiredadditional time base circuits may be added and synchronized with thepositive pulses, but since in comparison of electrical impulses eachsignal usually bears some harmonic relation to some of the others twotime bases are sufficient for general observation.

In operation of the circuit as shown in FIGS. 1 and 2, raising thepotential on the vertical deflection plates will raise the electron beamof the oscilloscope to provide a separate trace for each signal as itappears on the oscilloscope screen. The pulses from the tubes T-lfi,T41, and T-lZ when placed on the upper deflection plate raise the axisWhile the signals from T-li6, T-17 and T-lS are on the screen and thepulses from T-13, T14, and T45 when placed on the lower deflection platelower the axis While tubes T49, T-ZO and T-21 are conducting.Manipulation of the controls thus permits the operator to use separateaxes for the separate signals, to super-impose one or more signals overone or more other signals, or to observe the separate signals single ortogether as desired.

From the foregoing it will be apparent that the principles of thisinvention are adaptable to many known types of electric circuits toprovide obvious improvements in operation and utility of variouselectric and electronic devices. Accordingly while separate embodimentsof this invention have been shown and described, this invention is notlimited to the specific uses described. For these reasons anymodifications or changes of this circuit which are within the scope ofthe hereunto appended claims are deemed to be a part of this invention.

I claim:

1. In combination in an electronic system of the multiplexing typetransmitting bursts of intelligence spaced from one another by apredetermined time interval, an oscillator for generating an alternatingwaveform of regulated frequency, a plurality of separate circuitscomprising phase shifting circuits having connection with the output ofsaid oscillator for effecting predetermined differing phase shifts ofthe separate waveforms of said separate circuits, a plurality of pulseforming circuits, one connected to the output of each of said phaseshifting circuits for forming pulses related to the phase shiftedwaveforms, a plurality of intelligence gating circuits connected onewith each pulse forming circuit at one output thereof, a plurality ofintelligence feeder circuits connected one with each gating circuitwhereby separate signals each modulated on a different frequencysub-carrier may be supplied to said gating circuits, each gating circuitincluding an electron tube connected as a cathode follower having anoutput connected to a common terminal, the gating circuits being adaptedto permit said bursts of intelligence from each of said intelligencefeeder circuits to pass to the common terminal during the existence ofthe corresponding gating pulse whereby time spaced pulses appear at theoutput of the pulse forming circuits and are transmitted by said commonterminal as repeating groups of time-spaced pulses each group containinga sampling of each of said feeder circuits.

2. An electronic switching circuit for use with oscilloscopes to providemeans for viewing a plurality of waveforms on the single oscilloscopescreen comprising an oscillator for generating an alternating currentsine wave voltage, a plurality of phase shifting circuits connected inparallel to the output of said oscillator for time-spacing the separatevoltage waveforms in the separate circuits, vacuum tube limiter circuitsin said separate circuits for squaring the waveform, peaking circuitsfor sharpening the waveform, pulse clipping means connected to saidpeaking circuits for biasing the positive going peaks and limiting thenegative going peaks, cathode followers connected to the output of saidpulse clipping circuits, separate signal carrying lines connected tosaid cathode followers for inducing separate signals on the resultanttimespaced positive pulses, lines connecting the output of said cathodefollowers to the vertical amplifiers of said oscilloscope, means foradjusting the amplitude of the output signals of each of said cathodefollowers, means connecting the output of one group of pulse clippingcircuits to the upper vertical plate of said oscilloscope, meansconnecting the output of a separate group of pulse clipping circuits tothe lower vertical plate of said oscilloscopes, and means arranged toadjust the amplitude of each of said pulses of said groups impressed onsaid vertical plates for selectively positioning the correspondingsignals on said oscilloscope.

3. An electronic switching'circuit for use with oscilloscopes to providemeans for viewing a plurality of waveforms on the single oscilloscopescreen comprising an oscillator for generating an alternating currentsine wave voltage, a plurality of phase shifting circuits connected inparallel to the output of said oscillator for time spacing the separatevoltage waveforms in the separate circuits, vacuum tube limitercircuits'in said separatecircuits for squaring the waveform, peakingcircuits for sharpening the waveform, pulse clipping means connected tosaid peaking circuits for biasing the positive going peaks and limitingthe negative going peaks, cathode followers connected to the output ofsaid pulse clipping circuits, sepa rate signal carrying lines connectedto said cathode followers for inducing separate signals on the resultanttime spaced positive pulses, lines connecting the output of said cathodefollowers to the vertical amplifiers of said oscilloscope, means foradjusting the amplitude of the output signals of each of said cathodefollowers, means connecting the output of one group of pulse clippingcircuits to the upper vertical plate of said oscilloscope, meansconnecting the output of a separate group of pulse clipping circuits tothe lower vertical plate of said oscilloscope, moans arranged to adjustthe amplitude of each of said pulses of said groups impressed on saidvertical plates for selectively positioning the corresponding signals onsaid oscilloscope, and separate time base circuits connected to theparaphase amplifier grids of the separate sweep generators of saidoscilloscope.

References Cited in the file of this patent UNITED STATES PATENTS1,194,820 Colpitts Aug. 15, 1916 2,009,438 Dudley July 30, 19352,092,442 Colwell Sept. 7, 1937 2,213,320 Mathes et al. Sept. 3, 19402,380,982 Mitchell Aug. 7, 1945 2,405,239 Seeley Aug. 6, 1946 2,413,440Farrington Dec. 31, 1946 2,419,546 Grieg Apr. 29, 1947 2,444,950 Nicholset al. July 13, 1948 2,455,283 Valley NOV. 30, 1948 2,459,131 MesnerJan. 11, 1949 2,479,920 Hansell Aug. 16, 1949 2,548,796 Houghton Apr.10, 1951 2,551,681 Lawrence May 8, 1951 2,559,644 Landon July 10, 19512,605,360 Trevor July 29, 1952

